\\[-1.8ex] Soil Heterogeneity & $-$0.134$^{***}$ & $-$0.072$^{***}$ & $-$0.064$^{***}$ & $-$0.049$^{**}$ & $-$0.055$^{**}$ & $-$0.066$^{***}$ \\ 
  & (0.047) & (0.024) & (0.023) & (0.021) & (0.023) & (0.025) \\ 
\\[-1.8ex] 
Observations & 101,132 & 101,132 & 101,132 & 101,132 & 101,132 & 101,132 \\ 
R$^{2}$ & 0.019 & 0.083 & 0.091 & 0.157 & 0.216 & 0.305 \\ 
